Impact of climate change on maize yield in China from 1979 to 2016

Climate change severely impacts agricultural production, which jeopardizes food security. China is the second largest maize producer in the world and also the largest consumer of maize. Analyzing the impact of climate change on maize yields can provide effective guidance to national and international economics and politics. Panel models are unable to determine the group-wise heteroscedasticity, cross-sectional correlation and autocorrelation of datasets, therefore we adopted the feasible generalized least square(FGLS) model to evaluate the impact of climate change on maize yields in China from 1979–2016 and got the following results:(1) During the 1979–2016 period, increases in temperature negatively impacted the maize yield of China. For every 1°C increase in temperature, the maize yield was reduced by 5.19 kg 667 m–2(1.7%). Precipitation increased only marginally during this time, and therefore its impact on the maize yield was negligible. For every 1 mm increase in precipitation, the maize yield increased by an insignificant amount of 0.043 kg 667 m–2(0.014%).(2) The impacts of climate change on maize yield differ spatially, with more significant impacts experienced in southern China. In this region, a 1°C increase in temperature resulted in a 7.49 kg 667 m–2 decrease in the maize yield, while the impact of temperature on the maize yield in northern China was insignificant. For every 1 mm increase in precipitation, the maize yield increased by 0.013 kg 667 m–2 in southern China and 0.066 kg 667 m–2 in northern China.(3) The resilience of the maize crop to climate change is strong. The marginal effect of temperature in both southern and northern China during the 1990–2016 period was smaller than that for the 1979–2016 period.     

基于格网的GCM数据修订分析未来海南岛农业水热资源的变化特征

以海南岛为研究区域，选用5个大气环流模式（GCMs）1970−1999年的逐日输出数据和同期地面气象观测数据，使用空间插值降尺度到0.5°×0.5°格网。以格网单元为基础，应用系统误差修订（修正值法或比值法）和多模式集合平均方法（贝叶斯模型平均法BMA或等权重平均法EW），训练与验证GCMs输出值并进行综合修订。在此基础上，分析RCP2.6、RCP4.5和RCP8.5情景下，未来海南岛近期（2020−2059年）和远期（2060−2099年）农业水热资源，包括年平均气温、1月平均气温、≥10℃积温、≥20℃积温、年降水量、1月降水量和≥20℃界限温度生长期间降水量的变化特征。结果表明：GCMs输出值的系统误差和BMA权重系数在格网间存在较大的空间差异，且GCMs输出值低估逐日最高气温约3.55℃，高估逐日最低气温约1.19℃，逐日降水量仅为观测值的54.35%。基于格网的综合修订，可有效降低GCMs输出值在空间上的不确定性，BMA与EW的修订结果相似，均优于单一GCM模式。通过格网BMA综合修订后，最高气温、最低气温和降水量在验证期的相关系数r分别约提升0.10、0.07和0.06；均方根误差RMSE分别约降低2.38℃、1.01℃和1.01mm；较单一GCM相对观测值的偏差平均约减少3.25℃、1.13℃和25.67mm。未来海南岛农业热量资源在空间上主要表现为从中部向外围逐渐升高，高温主要分布在南部至西部沿海地区，年平均气温的增幅全岛较为接近，1月平均气温、≥10℃积温和≥20℃积温的增幅分别表现为由东向西、由北向南和由中部向外围递减。在时间上，RCP8.5情景下所有农业热量资源均为极显著增加且增温最快，RCP4.5情景为先增加后平缓，RCP2.6情景较为平缓，远期无显著增温。未来海南岛降水资源在空间上转为由东向西逐步递减的格局，南部和北部沿海地区降水变率增加，西部和中部降水变率减少，在时间上无显著变化趋势。随着未来海南岛气候变暖和降水格局的改变，农作物适宜种植面积扩大，会对农业生产带来巨大挑战，应提前布局，做好趋利避害。     

云南不同气候带农业气候资源变化特征研究

为分析全省平均以及各气候带光能、热量、水分资源的时空变化特征,使用云南115站及6个气候带代表站1961—2018年的气候要素计算各地农业气候资源统计量。结果表明,光能资源变化以减少趋势为主,出现显著突变,各气候带太阳辐射变化可能会引起云南太阳辐射高低值中心发生变化,2009年以来辐射明显增加可能会导致太阳辐射出现新的变化趋势和突变点;热量资源一致显著增加,喜凉及喜温作物的活动积温、积温持续时间及无霜期长度均显著增加,并且呈现初日提前、终日推后的趋势,对作物生长有利;水分资源总体呈现减少趋势,尤其21世纪以来下降趋势明显,亚热带地区暖干化现象突出,干旱风险等级较高。     

校园环境噪声监测与评价--以华中师范大学为例

环境噪声是环境质量评价的重要指标。通过噪声监测实验,记录了华中师范大学校园内的噪声污染数据,根据国家标准评估了校园环境噪声状况。试验采用网络剖分法,分别于昼间7:30~10:00和夜间22:00~22:55两个时间段对等效声级进行了测定。实验结果表明:昼间噪声污染更为严重,平均噪声超标率达到26%,夜间噪声污染相对较轻,但噪声超标率也达到19%。校园内不同功能区的噪声来源不同,工程施工产生的噪声是主要的污染源,影响比重达到58%。根据实验结果,校园声环境质量一般,需要对现状提出合理的改进建议。     

Soil protection for a sustainable future: options for a soil monitoring network for Ireland

The increased recognition of the importance of soil is reflected in the UN Post‐2015 Development Agenda with sustainable development goals that directly and indirectly relate to soil quality and protection. Despite a lack of legally binding legislation for soil protection, the European Commission remains committed to the objective of soil protection. However, the achievement of a legally binding framework for soil protection relies on the implementation of a soil monitoring network (SMN) that can detect changes to soil quality over time. As beneficiaries do not pay for the provision of soil information, the options for soil monitoring are limited. The use of existing data sets should be considered first. Using Ireland as an example, this research explored the opportunities for a SMN for Ireland considering three existing national data sets. The options for a SMN are considered in terms of their spatial and stratified distribution, the parameters to be measured and an economic analysis of the options proposed. This research finds that for Ireland, either a 10 or a 16 km² grid interval stratified by land use and drainage class offers the best potential in relation to the spatial distribution of existing data sets to reflect local data at a national level. With existing data, the stratified SIS data using the 16 km² grid offers the best value for money, with baseline costs for analysis, excluding field costs, of between €706 481 and €2.8 million. Acknowledging the impossibility of measuring all parameters with ideal frequency, this study proposes a two‐tier system for optimized monitoring frequency. Parameters must anticipate future policy requirements. Finally, the implementation of a SMN must be accompanied by standardized methods, defined thresholds and action mandates to maintain soil quality within allowable limits.     

Studies on Tomato Seedling Quality Indices Under Simulated Shipping and Storage Conditions

Indices of the tomato seedling quality maintenance level after production before field planting were studied through simulated experiments, small--scale operation, indoor analyses and measurements, and field observation. The results showed that under simulated shipping and storage conditions, seedling quality change following different durations (days) of shipping and storage was correlated significantly or even very significantly with certain physiological and morphological indices. With various measured indices following different periods of shipping and storage treatment subjected to multinomial successive regressive correlation analysis, the principal factors influencing seedling quality maintenance level are identified to be chlorophyll content→dry short weight→ leaf freshness index in order of their importance. Significance analysis with multinomial fitted equation indicated that correlations between any one of above three factors and the growth index after field planting reached very significant difference level.     

两株新分离的APMV-I毒株感染SPF鸡的超微病理变化

将APMV-I鹅源分离株YG97鸡源分离株Y98和NDV强毒株F48E8感染SPF鸡，运用透射电镜观察该2株病毒分离株对机体细胞的影响，结果显示3株禽副黏病毒均引起机体肝、胰、脾、肾、心、胃、十二指肠和直肠等实质器官组织细胞的超微病变，如黏膜上皮细胞多处受损，表面微绒毛脱落；实质细胞核固缩、凝聚、凹陷、核多形性，线粒体嵴断裂、空泡样变、膜溶解，粗面内质网扩张、囊泡变，细胞浆的囊泡内及细胞浆内存在有囊膜的成熟病毒粒子等，但YG97和Y98对不同实质器官的组织细胞超微病变程度不一：胃、肝、胰、脾、肾超微病变比心脏的超微病变严重。电镜观察结果还表明：3株禽副黏病毒引起宿主细胞的超微病变有2种形式：坏死性病变和凋亡性病变。     

基于模糊建模的混炼胶粘度测量

提出了一种在线测量混炼胶粘度的新方法．该方法以模糊建模技术为基础，综合考虑混炼过程各因素对胶料粘度的影响，建立起胶料粘度的在线测量模型．在模糊建模中，采用T-S模型描述胶料粘度变化的非线性过程，提出了一种基于相似性判别的模糊聚类算法以自动确定合适的聚类组数目，并用实数编码的遗传算法优化全局参数，从而获得了规则简化的、具有较高精度的模糊模型．根据此方法，设计了测量装置，并进行了现场试验．试验结果表明模糊模型输出与实验室测量值基本一致，平均误差较低且最大误差未超过1门尼．该方法较大地提高了橡胶混炼的生产效率，为粘度最优控制奠定了基础．     

主体意识的归隐 显现与本质寻求——意识形态的质性裂变

随着意识形态理论的发展,意识形态的所指已经发生了实质性的功能性裂变。它的发生逻辑隐含了主体意识的无意识的归隐与自为的显现,而主体意识与意识形态的本质寻求无论是隐匿性的暗示或遮蔽性的深层所指,都与意识形态的功能性机制及社会历史性的存在状况具备极强的内在一致性。     

金属热防护系统多层隔热材料的传热分析及参数优化

采用能量平衡方程和离散坐标法近似地建立了金属热防护系统多层隔热材料的一维稳态传热的数学模型，并利用遗传算法和纤维隔热材料的有效导热系数试验数据求解传热反问题，从而得到了模型中的纤维隔热材料的辐射衰减系数、反照率和隔热屏表面辐射发射系数。最后，由实验测得了多层隔热材料的有效导热系数，验证了采用优化参数后，多层隔热材料的传热模型的正确性。